Climate models that predict continued loss of sea ice, the main habitat of polar bears, during summers are unreliable, said Palin, a Republican.

The announcement drew a strong response from the primary author of the listing petition.

"She's either grossly misinformed or intentionally misleading, and both are unbecoming," said Kassie Siegel of the Center for Biological Diversity. "Alaska deserves better."

Siegel said it was unconscionable for Palin to ignore overwhelming evidence of global warming's threat to sea ice, the polar bear's habitat.

"Even the Bush administration can't deny the reality of global warming," she said. "The governor is aligning herself and the state of Alaska with the most discredited, fringe, extreme viewpoints by denying this."

As marine mammals, polar bears are regulated by the federal government, not the state. Interior Secretary Dirk Kempthorne last week made the listing decision and said it was based on three findings.

A 2006 study by the U.S. Geological Survey concluded that far fewer polar bear cubs in the Beaufort Sea were surviving and that adult males weighed less and had smaller skulls than those captured and measured two decades previously — trends similar to observations in Canada's western Hudson Bay before a population drop.

A U.S. Geological Survey study completed last year as part of the petition process predicted polar bears in Alaska could be wiped out by 2050.

Kempthorne said last week he considered every point Palin made, and rejected them.

However, he sought to limit the economic effect of the decision with the inclusion of "administrative guidance" that said the listing would not be used to create back-door climate policy outside the normal system of political accountability.

He also said that the threat to polar bears did not come from the petroleum industry.

In response, conservation groups including the Center for Biological Diversity, Greenpeace and the Natural Resources Defense Council are seeking to overturn Kempthorne's administrative actions and seek limits on greenhouse gas emissions.

Palin and other state officials called arbitrary a decision to list a healthy species judging by what they deem uncertain modeling of future climate change and unproven long-term impact of any future climate change on the species.

State Natural Resources Commissioner Tom Irwin said it could have wide economic effects.

"Inappropriate implementation of this listing decision could result in widespread social and economic impacts, including increased power costs and further increases in fuel prices, without providing any more protection for the species," he said.

Deborah Williams, a former Interior Department special assistant for Alaska and an advocate in the state for global warming response, said Palin's lawsuit was not a prudent use of state money.

"Clearly Secretary Kempthorne put a tremendous amount of thought into the listing decision and concluded correctly that listing was required," she said.